Methods will be developed for the isolation of membrane proteins and glycoproteins from human red blood cells, lymphocytes, cultured cells, and different tumor cells. Some of the isolated proteins will be purified and characterized in terms of chemical composition, molecular weight and subunit structure, and peptide components, and by various immunologic assays. The in situ location of some membrane proteins will also be studied using conjugated antibodies for freeze-etching and electron microscopy. Lithium diiodosalicylate will be used to isolate glycoproteins from membranes of tumor cells which carry tumor-specific antigens. These will be purified and characterized, and antisera prepared for radio-immuno and other assays. Attempts will be made to determine which molecular components of the glycoproteins carry the specific determinants. Studies will also be carried out on the development of tumor-specific antigens in induced animal tumors and the interactions between soluble antigens and lymphoid cells.